<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<style type="text/css">
			.one{
				width: 100px;
				height: 100px;
				background: red;
			}
			.two{
				width: 50px;
				height: 50px;
				background: transparent;
			}
			
			.three{
				width: 100px;
				height: 100px;
				background: rgba(0,0,0,0.5);
			}
		</style>
	</head>
	<body>
		1.透明色<br /><br />
		<div class="one">
			p1
			<div class="two">p2</div>
		</div>
		<br /><br />
		
		2.rgba()的使用<br /><br />
		<div class="three"></div>
	</body>
</html>
